The most salient part of your question to me was the word user. How do you add functionality to benefit a user? Once you have a clear idea who your user is, and

The most salient part of your question to me was the word user. How do you add functionality to benefit a user? Once you have a clear idea who your user is, and what they want, the answer comes more naturally to you. For instance, if your user is someone who wants to know a piece of information, you can display that information. If there is logic to be handled depending on who the user is, you can google "nodejs authentication" and use a library to handle that for you. Everything is constructed in steps, and I don't think there's a magical barrier between writing your first lines of code and having useful functionality.